Transport temperature control units are used to maintain a desired temperature in a conditioned space inside an enclosure used for carrying cargo, such as in a trailer, truck or other transport container. Transport temperature control units generally include an evaporator assembly that transfers heat from the conditioned space to a refrigerant, and a condenser assembly that transfers heat from the refrigerant to the outside environment. The evaporator assembly typically includes an evaporator coil and air-moving apparatus. The air-moving apparatus draws relatively warm air from the conditioned space, moves the air through the evaporator coils, which extract heat from the air. The air-moving apparatus also returns the cooler air to the conditioned space. Similarly, the condenser assembly typically includes condenser coils and air-moving apparatus. The air-moving apparatus draws air from the outside environment through the condenser coils, which discharge heat into the air, and returns the heated air to the outside environment. Transport temperature control units also generally include a refrigerant compressor to compress the refrigerant and an expansion valve to decompress the refrigerant. The evaporator assembly, condenser assembly, compressor and other components in the temperature control unit require a power supply. Conventional transport temperature control units employ an engine, such as an internal combustion diesel engine, to supply the needed power.
A transport temperature control unit can be installed on the exterior of the enclosure, outside of the conditioned space. In the case of a truck, a typical mounting site for the transport temperature control unit is at the front of the enclosure, above the cab of the truck. In such a case usually there may be limited space for the transport temperature control unit. When the truck has a tilt cab, i.e., access to the truck engine is provided by swinging the body of the cab forward and away from the chassis, the space for a transport temperature control unit is even more limited. If the transport temperature control unit impinges upon the cab body""s swing radius, then the cab body may not be able to swing forward because the transport temperature control unit is in the way, or the transport temperature control unit may be damaged by the cab body as the cab body is swung.
To save space, part of the temperature control unit may be located wholly or partially inside the conditioned space of the container. Frequently the evaporator is placed largely or entirely within the conditioned space. It is generally undesirable, however, to locate the evaporator in the conditioned space, for several reasons. For example, an evaporator in the conditioned space takes up room that could be used to carry cargo. In addition, the evaporator could be easily damaged as cargo is moved about inside the conditioned space, by contact with the machinery used to move the cargo or by contact with the cargo itself.
The invention relates to a compact arrangement of the condenser and evaporator on a temperature controlled transportation unit. In one aspect, the invention presents a transport temperature control unit adapted to maintain a conditioned space at a desired temperature. The unit includes an electrically-powered condenser assembly and an electrically-powered evaporator assembly flow connected to the condenser assembly. The evaporator assembly adapted to be located outside the conditioned space, and the electrical power is supplied from a source external to the transport temperature control unit.
In one embodiment, the unit may be fixedly mounted to a cargo container. In another embodiment, the unit may be mounted to the cargo container so as to allow the unit to swing upward, thus providing clearance for a tilt-cab truck with a large swing radius.
In a another embodiment, the invention presents a temperature-controlled transport system. The system includes an enclosure for holding cargo and a compact transport temperature control unit.
In a further embodiment, the transport temperature control unit may include two evaporator sub-assemblies. The sub-assemblies may be flow connected in parallel, allowing a single unit to provide independent temperature regulation to two compartments.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.